<!doctype html>
<html>

<head>
    <meta charset="utf-8">

    <title>Hello React!</title>

    <script src="https://unpkg.com/react@16/umd/react.development.js"></script>
    <script src="https://unpkg.com/react-dom@16/umd/react-dom.development.js"></script>
    <script src="https://unpkg.com/babel-standalone@6.26.0/babel.js"></script>
</head>

<body>

    <div id="root"></div>

    <script type="text/babel">
      class App extends React.Component {
        render() {
            return (
                <h1>Hello World!</h1>
            )
        }
      }
      ReactDOM.render(<App />, document.getElementById('root'));
    </script>

</body>

</html>